The French ensemble Diabolus in Musica was founded in 1992 and focuses on French medieval and early renaissance music. It is probably less known than other ensembles of its kind. I knew it from various discs, but had never heard it in a live concert. A short tour across the Netherlands from 9 to 14 May allowed to make up for that. I attended the first concert which took place in the Church of the Community of Moravian Brethren in Zeist, a town east of Utrecht.

Antoine Guerber and his singers carried us back to the time of the Popes of Avignon, the 14th century. During the Avignon Papacy, as this period (1309-1377) is called, seven successive Popes resided in Avignon. This was the result of a conflict between the Papacy and the French crown (more about the background can be found at Wikipedia). In particular under the Popes Benedictus XII and Clemens VI Avignon became a centre of music and letters. The papal library was the largest in Europe. Several musicians and composers of fame worked for some time in Avignon, among them Philippe de Vitry - who was represented in the programme - and Johannes Ciconia.

The programme concentrated on music which may have been sung at the St Pierre chapel, also known as Chapelle Clémentine. In addition to the Grande Chapelle Benedictus created a private chapel, St Etienne, which included twelve singers. These were mostly from northern France, and as a result French music dominated the repertoire sung in the liturgy. No music sung in the chapel has been preserved, but manuscripts from the same time give some idea of the kind of music which was sung, scored for two to four voices. The central element was music for daily Mass celebrations. During the renaissance many composers wrote masses, often using material from pre-existing music (so-called parody masses). However, complete settings of the Ordinary (Kyrie, Gloria, Credo, Sanctus & Benedictus, Agnus Dei) did not exist at the time of the Avignon Papacy. The earliest mass by a single composer and intended as a unity is Guillaume de Machaut's Messe Nostre Dame, probably written in the early 1360s for Reims Cathedral. Some anonymous masses have been preserved, such as the Messe de Tournai, but there is no proof that these were written by a single composer and intended as a cycle.

Therefore Guerber had put together two masses from various sources. The first was largely anonymous, but opened with a Kyrie by a composer with the name of Guymont; this three-part setting is the only piece by him which has come down to us. The second section was a Gloria called Gloria et Verus Homo Deus; it is an example of a trope: new lyrics, usually related to a specific time of the ecclesiastical year, is inserted into an existing liturgical text. Here it was heard nearly at the end; I don't know what the text was about, because the programme had omitted it. More tropes appeared in the second mass: both the Kyrie (Ave desiderii/In partu mirabilis) and the Sanctus (Sanans fragilia/Salva nos) had additional texts. The first four sections were again anonymous; this time it was the Agnus Dei which was attributed to a composer: Heinricus de Libero Castro, who is possibly identical with Heinrich Laufenberg (c1390-1460), a German-Swiss poet and musician. The programme gave the years of birth and death of Laufenberg, so one may conclude that Guerber believes it is one and the same person. However, it is impossible to prove and one wonders how a piece from his pen may have made it to Avignon. In New Grove I could not find any connection between Laufenberg and France.

In between the masses were several pieces by anonymous composers as well as Philippe de Vitry. As I wrote above he worked for some time in Avignon. He is also probably the author of the treatise which described in detail the compositional style he labelled Ars Nova (c1322). This style - dominating the music scene from c1320 to the death of Machaut in 1377 - is what linked the pieces in the programme. One of its features is the use of the technique known as hoquetus: the medieval term for a contrapuntal technique of manipulating silence as a precise mensural value. Its use was not confined to the Ars Nova, but was often used, for instance by Vitry. We heard it, for instance, in his Petre Clemens/Lugentium, but also in Guymont's Kyrie. This ended with another stylistic device: a tremolo in all the voices, which also appeared in several other pieces.

The two masses were performed by the entire ensemble, but in some sections it was split into two groups of three which then alternated in the various sections of a mass movement. The other pieces were mostly sung with one voice per part, and here Guerber took a back seat, leaving it to the singers themselves to take care of the musical discourse. This repertoire is quite spectacular because of the use of very peculiar compositional and vocal techniques; these are quite different from what we use to hear in later repertoire. This kind of music is not that often performed, not even in the Festival Early Music Utrecht. Therefore this was a good opportunity to get to know it better and to hear it in a live performance rather than on disc.

However, having heard several discs by this ensemble I was a little disappointed about its performances. That was largely due to one of the tenors - probably Olivier Germond - who produced often a rather penetrating and sharp sound which was not nice to listen to and also damaged the ensemble. In addition he often used quite some vibrato. This may have had less impact in a different acoustic. The Church of the Community of Moravian Brethren is a wonderful venue, but has a kind of intimacy which works against the music sung at this concert. I would have liked to hear it in a larger church, for instance the Pieterskerk in Utrecht, and consequently a more reverberant acoustic. Another aspect of the performance about which I had my doubts was the pretty strong dynamic differences. Some passages were sung very loud, others pretty soft. I could not figure out what the reasons may be for this practice.

That said, I was happy to be there, and the audience will certainly have been impressed by the brilliance of the repertoire, which deserves to be better known.